PDO drivers no value in Windows，有需要的朋友可以參考下。

學習php程式設計遇到

Uncaught exception 'PDOException' with message 'could not find driver'

或者

Undefined class constant 'MYSQL_ATTR_INIT_COMMAND'

整兩個問題,網上找了很多資料,很多是這樣解決的

配置php.ini檔案新增extension=php_pdo_mysql.dll，這樣就開啟pdomysql擴充套件庫

但是我沒有解決問題,問題還是老樣子,後來在stackoverflow 找到了問題所在

問題出在了

extension_dir = "ext"

改成絕對路徑就可以了

例如：

extension_dir = "D:/php-5.4.11-Win32-VC9-x86/ext"

; Directory in which the loadable extensions (modules) reside. ;http://php.net/extension-dir ; extension_dir = "./" ; On windows: extension_dir = "D:/php-5.4.11-Win32-VC9-x86/ext
 

原因

in php.ini andphp -mwas starting fine and reporting that it loaded pdo_mysql, but when I ran phpinfo.php through apache, the driver was missing.

I fixed it by changing theextension_dirto anabsolute path. I'm guessing it got confused when running through Apache and made it relative to something else.　　

我固定它通過改變extension_dir絕對路徑。我猜它混淆了執行時通過Apache和相對於別的東西。